49:1 unun wire lengthsfannie flagg grease
Picture 1 of 9. Use with other lengths can potentially damage the transformer depending on power level in use. 2 0 obj For best results, use the Wire Length Feet 1.8 MHz 3.7 MHz 5.3 MHz 7.1 MHz 10.1 MHz 14.2 MHz 18.1 MHz 21.2 MHz 24.9 MHz 28.5 MHz 50.1 MHz understand its properties. 73. JACK, VE3EED Theme designed by Papathemes. unavailable, a random wire can save the day, but it is important to Lengths to avoid are not always the same as The length should be calculated based on the lowest frequency to be worked. An end fed antenna consists of a wire fed on its end, the length of that wire is not resonant with any frequency or frequencies you will be using it on. 0 While I have not done so yet, I plan on gluing the test cap to the back of the junction box. End fed 9:1 58ft wire and 17ft counterpose wire touching ground. 4 0 obj The 9:1 may work best with that length wire and a tuner, but some say that length is undesirable for the hf HAM bands. excellent page for EFHW info - or, addressed below, to cut the wire Performance is ASTOUNDING, far exceeding my expectations. For reasons that I do not understand, adding a capacitor between the coax conductor wire (untwisted free end of short wire) and the ground (twisted free ends of long and short wire) can increase the functional bandwidth of the antenna on the higher HF frequencies. <>/Metadata 239 0 R/ViewerPreferences 240 0 R>> We hoisted the free end of the antenna wire approximately 30 feet into a tree. V#X~[Z?\ZcX:-Y?&Y?IqTnayZ{jTZOub}=UTWu1G>o.,RaT c=W>:sECXTkc=X Note: My (A to B) length was 6 inches. /ProcSet 7 0 R >> Mike ab3ap, Editors note: Many thanks to Jack, VE3EDD (SK)and Mike, AB3APfor sharing their math and computerskills with us. 73, 4 0 obj >> The fewer bands, the fewer high impedance regions to avoid. The counterpoise wire, This transformer is designed to be used with an end fed, Approx. In fact, the 9:1 unun that I built is actually an autotransformer. endobj I used 2000 and 1000 ohm resistors in series connected to the proper unun wires with alligator clips for a total of 3000 ohms. Multiples are on C and The Nelson antenna 9 to 1 unun did the trick. This is a followup video to #344 where I assembled the 49:1 UNUN kit from HF-Kits / ARRL. AndWhat Is It Used For In Antennas? bands you're intested in in a vector like the example below, by typing. The matching unit The impedance at the end of a half wave antenna is somewhere between 2000-5000 Ohms. endobj JavaScript is disabled. So for example 80m could range in length from 120 to 133 feet. 3 to31 MHz - up to 1kW intermittent (50% duty cycle). 9:1 or 49:1 unun for end-fed long/random wire? Just an FYI that I thought you might be interested in. Gil Gruson 1 Campaign | Comines, France $0 USD 0 backers 0% of $3,450 Flexible Goal Follow Story FAQ Updates 0 Comments 0 Prototype The project team has a working demo, not the final product. This was 9m vertically metres up a fishing pole and then about 5.8m out. I took a literally random length of 14 gauge house wire and attached a banana plug to be shoved into the antenna port of the tuner. Cut the center conductor wire (free untwisted end of short wire) of the unun to the correct size, scrape the enamel insulation off of the free end with a box cutter, and solder it to the SO239 connector. I actually did this first and before the connector was bolted to the box. 9:1 UnUn End Fed Long Wire Lengths - Pretty Simple. Post Reviews endobj endobj The QRP End-Fed Half-Wave Antenna 49:1 Transformer Building a great impedance transformer for Ham Radio end-fed wire antennas. The major point of this message is to tell you that approximately 20 minutes after I connected the balun unit to the antenna, I made contact with a gentleman in Italy-my first European contact!! the program as I did, above, for my K1. The "9:1 UNUN" are for random length wire antennas fed at the end. x][~ XwiH:99gn`1-wz;n[VbW7JH4D]>}>y/D_^7,yyx}s*nveo>mn|6k7GMY4%" M)?O|'opw8o1\5JNe:9hTc5@Ik~aE%O^0$ 0E 'BX2?R!t&^E"3oqbW |${boEU>jU:]bQW?4, u1'^`oQ_4E 0~y L^'y}-RHV8L KSZ?mF4lTv'r^mF|":e}?VdTm7bGR]PchDpb*{*HGJ-m)bC!EX"iM%8L7O7-=jcn+D{_' I HH~v70J^9$.7m]knq)L(UQ%OrK:nn!8*EP Start winding the toroid with the twisted wires at loop #1 (see schematic below). document.getElementById("copyright_year").innerHTML = new Date().getFullYear(); (Note: I am not satisfied with this part of the project, so I will describe it here briefly. 5 0 obj Yes, with the recent surge in popularity of the end-fed half-wave antenna, the 49:1 balun has also become the defacto ratio for use with them. The graph below shows lengths to avoid for different collections of bands. Contact Here Is a 250 Watt Home-Brew That I Made In about an Hour. First, it is important to understand the difference between the end fed half wave and a random wire (or "long wire") antenna: the random wire is just a piece of wire that is matched to 50 Ohm impedance using an antenna coupler, sometimes adding a 9:1 unun. q Twist the short and long wires together starting at an end of each wire. This transformer converts the impedance at the end . This is considered a random wire end fed antenna, not to be confused with a half wave end fed antenna which uses a 49:1 or 64:1 unun and a wire that is a half wave length. this I'm consistently pleased with the quality and ease of use of Balun Designs products and look forward to my next purchase in the future. Par EF 20 and par EF 40 (I realize for 17m I would prob just add that band to a 49:1 balun) That's that my question is. JC[ d8O[UKKQ{yZ{G 'Upno_*~8uo a@G`' zxUHXW&`}mEp`?i0 oE:N0-/t"t.-? , The "Best" Random Wire Antenna Lengths He was so impressed that he purchased a 9:1 unit from you, his will be delivered Saturday. Meet 'Balun One Nine', a small, cost-effective balun. To summarise the results WRT to reference antenna consisting of 30ft wire vertical fed with auto- Here I show finalizing the antenna, getting it in the air, and run. (wlSR9dJ_x%+VHX4FRr 3>;g^x%g'wkJu,i~#Q"2|WGf[!_m]#&1$)R.{--" 'dGO;=_B$T}". 1. He used 300 ohm twin-lead and a 4:1 UNUN, with a 1:1 current choke between the UNUN and the coax to the tuner and transceiver: The full-size "flimsy" (ref. <> %%EOF 1 0 obj Kj8~q7c? The magic lengths to use with the End Fed longwire is 29, 35.5, 41, 58, 71 and 84 feet I use a 29 foot wire with my PackTenna 9:1 balun for 40m-10m and then add a 28 foot length for better coverage on 80m when needed. The popular End-Fed Half-Wave (EFHW) Antenna is an easily portable, high-impedance (2,000-4,000 ohm) wire antenna that resonates on its fundamental frequency and all harmonics above. A standard recommendation (see QST, March 1936, p. 32, "An Unorthodox The 49:1 unun with 3000 ohms of resistance shows a VSWR under 10:1 from 160M to 15M, and less than 3:1 from 80M to 20M. SWR will vary based on topography, wire orientation and use of ground or counterpoise. I'm looking forward to getting off work and hitting 40 & 20 meters again!! $119.95. I will also find some sort of heat resistant packing material to help hold the transformer in place. The 49:1, shown in my previous message, is meant for the EFHW that are fed close to or on the half wave (highest impedance) point. /Creator (XnView) , Most matching problems occur when the antenna system I included the tools I used to analyze the transformer as well; this is only necessary if you are interested in analyzing your project. but instead of the Jaycar core, we used an Amidon FT-240-43; anyhow, we also followed the UnUn with a 1:1 guanella choke and boxed everything, at that point, we . I connected the free twisted end of the short and long wires (the ground) the chassis wire (ground) of my homemade testing jig with alligator clip. I sent him the link to the 49:1 unit to get his feedback. https://elginradio.wordpress.com/2017/10/17/end-fed-half-wave-antennas/. 3. <> gnuplot RFI Tips and Tricks Repeater Builders endobj Do what works best! Balun Designs. Privacy Policy A good place to start is the formula 468 / f (MHz) for a 1/2 wavelength wire antenna. are blocked out because an antenna should be at least that long. There are numerous configurations available online that will accomplish this on multiple bands (Google search "end fed half wave antennas"). /Resources << 3 0 obj This undesired reflection of RF power back toward the transceiver is identified as a high voltage standing wave ratio (VSWR or SWR). This unit is a Balun Designs, in collaboration with Fair Rite products, has developed what we consider to be the best single core 1:1 feedline isolation balun available today. Usually any wire length that is non resonant, like those shown above, will work with the 4:1 ratio. are easily converted to half wavelengths by the famous 468/f generally The unun was floating at about 15 feet above ground. So is an essential piece of gear to have. Best SWR was . The most important length is one that is non-resonant on any band. You can take one of these 49:1 transformers and use the 468/freq (Mhz) formula to calculate the length you need in feet. The beauty of the halfwave antenna is it's a complete antenna in the sense it needs no counterpoise. I did not want to put the transformer in the housing until I tested it. ?7{*. When used with the stated Balun Designsis now offering a low power alternative for those who want to use an End Fed Half Wave for portable or temporary installations. SO-239 connectors are silver plated with Teflon insulation. The most common question I get asked is what is the correct length for my End Fed Long Wire Antenna? (The numbers aboveare a great start, thanks to Jack and Mike! <>/ExtGState<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 612 792] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> Hi guys,not really hfu related,but I tought I might ask here as I have my account. presents an extremely high impedance to the tu UJM-49-1 $56.99 Save up to 6% when you buy more. << Any SWR measurement taken with the transformer at the feedpoint should not exceed 1.5:1withNOtuner in use. Some of these numbers are too close to squeeze in between them. Winding 1:64 Matching Auto Transformer on the FT240-43 core. The 49:1 End Fed Half Wave Antenna is very popular choice for home & field use, Ideal for limited space and stealth applications. %PDF-1.7 For instance, to work 40m be sure the antenna is at least 10m or 33' long. endobj Prescott Hamfest 2023 Saturday - May 13, 2023 - 0800 to 1200 MST Granville Elementary School 5250 Stover Drive, Prescott Valley, AZ 86314 The 2023 Prescott Hamfest is co-sponsored by the Yavapai Amateur Radio Club (YARC) and the Amateur Radio Council of Arizona (ARCA). I have not done this yet. x@ 3 0 obj =======================, More on Random Wire Lengths from Mike, AB3AP (06-29-2012), I was surfing around Hamuniverse.com and found thIs page on random wire antennas: Enclosure Depth: 1.250 in. endobj Hopefully these random wire length calculations will help us all make this "easy" antenna work better! We have also installed an additionalstud which can be used for a separate counterpoise wire rather than forcing the use of the feedline's coax shield. Because I had some spare Cu-Wire I wound another 1:49 Unun on a smaller FT-140-43 toroid and tried different capacitors between feedline and ground (to compensate for the 10m band). It is used fornon-resonant verticals like 43 foot or 33 foot Or Wire antennas like an End-Fed1/2 Wave Multiple Length Wire Antenna. 7 0 obj well, the main antenna wire goes to the 9:1 UnUn "+" connector, the vertical counterpoise (insulated !) Lengths of a half-wave or multiple must be avoided. google_ad_height = 600; SSTV Figure 3 Wiring of the 9:1 voltage unun. A Balun is used to match a balanced line to an unbalanced line. Legal Stuff 9 0 obj For example a 32 foot length is actually a half wave on 20m with an impedance of about 3500 ohms and requires a 50:1 balun. It will be good for 15m, and 10m. Picture Information. and leave the unun on the ground. I say run what you got and don't worry about it. <>>> Typically unbalanced = 50/75 ohms too unbalanced = 450/675 ohms. You'll want to have that wire up as high as you can get.. What these lengths are depend on your tuner and also the wire's surroundings and also the ground system. Let the now free end of the short wire hang down from the toroid. End Fed Half Wave Antenna Coupler Schematic - 7-30MHz. << The length of enamelled copper wire per winding for the T-200-2 powdered iron toroid core is determined by length per winding = 50mm per turn plus 250mm tails. Lowest Band of Operation: 160 meters Highest Band of Operation: 10 meters Additional Information LDG Electronics RU-9:1 Unun BUILD INSTRUCTIONS FOR 49:1 UNUN IMPEDEDENCE TRANSFORMER: WX1MAR and I brought the DIY 49:1 unun with a borrowed antenna radiator wire cut for 20M half-wavelength to Ashland State Park K-2417 in Massachusetts for a Parks-on-the-Air (POTA) activation. , This is a partial reprint (with permission) of an excellent series of articles published by KV5R This calculates to 4.2 m or 14 ft for an 80m end-fed. A small ring terminal for 14ga wire that fits these screws would be helpful too. Suggested wire lengths for 1-61 MHz operation (measured from Bullet wire point): Bands Covered (meters) Wire Length (feet) Minimum Coax Length (feet) 40-30-20-15. You have to stay away from a half wavelength on any frequency. 9:1 Unun 1.5-54MHz 2kW 9132S. There are so many new frequencies to stay away from, that it gets pretty tricky for the longer wires. /Name /Im0 Some important and helpful references I used for this work: https://elginradio.wordpress.com/2017/10/17/end-fed-half-wave-antennas/. 6 Screws/ Nuts/ Washers/Wing Nuts And Ring Connectors, 1 X Mica Capacitors 100pF 500V 5%(Mouser Electronics), 1 x 4 in. for your country and favorite modes of operation. 35. I usually go with a 3.2k transformation wire winding ratio of 8:1 which is a final impedance conversion of 64:1 (50ohm * 64 = 3.2k ohm). The WorldwideDX Radio Forum was originally established in 2001. As typically Because I'm more visually oriented I then plotted the many overlapping "red zones" and ended up with the page at: I'm not saying aliens are in the radio, but aliens definitely are in the radio. However, the list has been revised and is good for wires as long as 500 feet. In addition to multiples, The random wire antenna is probably one of the least expensive, easiest and cheapest HF antennas to use if you have a tuner and you want to get the "most" out of a length of "random" wire without having to pull out that calculator, doing the math, getting the center insulator built orbought, running the feedline, and all the rest that goes with putting up a more elaborate antenna. I got three FT240-43 toroids (two would be lighter, but three increases the curie point so it can handle longer duty cycles), a spool of the 14 gauge enameled wire . So for 80 meters (say 3.525 MHz) this gives you about 133' of wire. Repeater Basics Anyway, an old friend mentioned 'MyAntenna.com' but they were closed for the summer. The fewer bands, the fewer high impedance regions to avoid. Antenna Safety! bands as possible. Vacation Closure - See Homepage for Next Availability. /&KWA7{L=D]g0Z!F9;V{zL[h-D,u(.9rg(RHI{f t*C/?? These are sometimes known as a Magnetic Longwire Balun. I wrote a small C program that does just what Jack did, butI used the band edges. This transformer is designed to be used with an end fed half wavelength of wire only. Tune Around! A few more comments about this 49:1 autotransformer EFHW design. u?X`f0&/Ri;W0Tn_*TX:ug the C code, in Matlab or Octave get a plot by simply putting the I only used two screws instead of four. Just add or subtract as needed a little at a time toget the best compromise. %PDF-1.5 Bullet 50:450 (9:1) HF Unun, 1.8-61 MHz, 1500 Watts, End Fed Antennas. Continue twisting the entire length of the short wire. Having the option to switch rapidly between 49:1 and 64:1 should prove to be a really nice feature.. x 2 in. At this point, Ive only used the 49:1 tap, but plan to take the 64131 whenever I operate portable. >> , Reprinted with permission of Hamuniverse, this is an excellent explanation of SWR and how to best me A level of 500-600 watts is the maximum with a further reduction onany band measuringabove 3:1. June 8, 2022 at 9:17 am. Liquidtight NM 90-Degree Connector(Home Depot). Turns 1 & 2 are primary windings (the short wire).